In the prior art as disclosed, for example, in U.S. Pat. Nos. 3,952,516 and 4,366,673 issued to Ellisworth W. Lapp, there is shown a portable manually operatable pressure amplification device for increasing the pressure from a low pressure source, such as that found on a utility truck, to a hand-held, ,high pressure actuated tool, such as a crimping tool used by a utility lineman. In such devices, it is known to have supply and return low pressure lines, as well as high pressure lines to the tool. The pressure in such devices is controlled by an adjustable pressure relief valve. The devices shown in these patents use a complicated arrangement which includes a high pressure axial plunger pump with a cam and a multiplicity of actuating arms in a plurality of holes; as well as a rotary scavenging pump to aid in removing the oil when the plunger of the crimping tool is on the return stroke. There is also a four-way valve to control the flow of fluid from the high pressure device to and from the tool.